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HCCI – Diagnostics and Control. Prof. Bengt Johansson Div. of Combustion Engines, Dept. of Heat and Power Engineering,. bengt.johansson@vok.lth.se www.vok.lth.se. Outline. Current engines HCCI in general HCCI in Lund, some results Production. Normal SI engine fuel consumption.

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Hcci diagnostics and control

HCCI – Diagnostics and Control

Prof. Bengt Johansson

Div. of Combustion Engines,

Dept. of Heat and Power Engineering,

bengt.johansson@vok.lth.se

www.vok.lth.se


Outline
Outline

  • Current engines

  • HCCI in general

  • HCCI in Lund, some results

  • Production



Introduction

Lean limit

100%

Catalyst Efficiency

99%

98%

0.8

1.0

1.5

2.0

2.5

5.0

SI engine - part load improvement

Stoichiometric premixed charge SI engine

- Low part load efficiency

+ Low emissions with 3-way catalyst

Lean burn premixed charge SI engine

+ Reduced pumping work

 improved part load efficiency

- Increased HC and NOx

Stratified charge SI engine - GDI

+ Removed pumping work 

much improved part load efficiency

- Large problem with NOx and PM

HCCI

+ Removed pumping work 

much improved part load efficiency

+ Shorter combustion period 

improved overall efficiency

- Engine control problem



Diesel engine ci
Diesel Engine (CI)

  • Large problems with emissions of NOx and PM

  • High fuel efficiency (low CO2 emission)


Hcci emissions
HCCI Emissions

AutoTechnology

Oct. 2002, p 54

HCCI

0,01

USA 2007

*

PM

0,00

0,05

0

0,5

NOx



Hcci activities in lund
HCCI activities in Lund

  • Basic engine studies

  • Laser diagnostics

  • Combustion modeling - Chemical kinetics

  • Closed loop combustion control


Experimental facilities single cylinder engines
Experimental facilities – single cylinder engines

Scania 2 liter

(Volvo 1.6 liter)

Volvo/Alvar 0.5 liter VCR

Old Hot bulb engine


Multicylinder engines for hcci control
Multicylinder engines for HCCI control

Scania 12 liter 6 cylinder dual fuel

Volvo 12 liter 6 cylinder VGT

Volvo 3 liter 6 cylinder VVT

Saab 1.6 liter 5 cylinder VCR/FTM



Hcci activities in lund1
HCCI activities in Lund

  • Basic engine studies

  • Laser diagnostics

  • Combustion modeling - Chemical kinetics

  • Closed loop combustion control






Low nox from hcci mode
Low NOx from HCCI mode

Gasoline & Diesel fuel

0.05

100% Gas

l

=3.0

0.045

65% Gas

n=1000 rpm

40% Gas

0.04

20% Gas

0% Gas

0.035

0.03

Specific NOx emissions [g/kWh]

0.025

0.02

0.015

0.01

0.005

0

10

15

20

25

Compression Ratio


With variable compression ratio vcr the hcci engine can use any liquid or gaseous fuel
With Variable Compression Ratio, VCR, the HCCI engine can useANYliquid or gaseous fuel!




Turbulence and geometry effects on HCCI

Experimental setup

Square bowl-in-piston

Disc

Swirl Ratio=2.8

HS case

Swirl Ratio=2.0

LS case


Turbulence and geometry effects on HCCI

4

Disc, LS Head

Centre Position

Disc, HS Head

3.5

Square, LS Head

Square, HS Head

3

2.5

Turbulence [m/s]

2

1.5

1

0.5

0

-50

-40

-30

-20

-10

0

10

20

30

40

50

Crank Angle [CAD]

Turbulence


Turbulence and geometry effects on HCCI

8

Disc, LS Head

Side Position

Disc, HS Head

7

Square, LS Head

Square, HS Head

6

5

Turbulence [m/s]

4

3

2

1

0

-50

-40

-30

-20

-10

0

10

20

30

40

50

Crank Angle [CAD]

Turbulence

Different scale


Turbulence and geometry effects on HCCI

800

Disc, LS Head

SOC=-2 CAD

Disc, HS Head

700

Square, LS Head

Square, HS Head

600

500

Rate of Heat Release [J/CAD]

400

300

200

100

TDC

0

-5

0

5

10

°

Crank Angle [

ATDC]

Rate of Heat Release


Hcci activities in lund2
HCCI activities in Lund

  • Basic engine studies

  • Laser diagnostics

  • Combustion modeling - Chemical kinetics

  • Closed loop combustion control


The influence of charge heterogeneity on the hcci combustion process
The influence of Charge Heterogeneity on the HCCI Combustion Process (?)


Fuel distribution prior to combustion
Fuel DistributionPrior to Combustion

With port-injection

With mixing tank


Tracer PLIF after Auto-ignition

With port-injection

With mixing tank


OH PLIF Imaging

With port-injection

With mixing tank



Multi YAG-Laser System

Ordinary laser

t

Multiple pulse laser

t

  • Single/Double pulse operation

  • 4 Pulses:Time separation (0-100ms)

  • 8 Pulses:Time separation (6-145µs)

  • Wavelengths:532nm and 266nm

  • Dye-laser for tuneable operation


High Speed Camera

  • 8 independent CCD’s, 576x384 pixels 10 ns temporal resolution

  • Optional image intensifier  UV sensitive 1 µs temporal resolution


Cyl. Volume 1951 cm3

Bore 127 mm

Stroke 154 mm

Comp. Ratio 16:1

Chamber design Pancake

Fuel Ethanol

Lambda 3.85

Experimental setup(Scania)


2 ATDC

2.5 ATDC

3 ATDC

3.5 ATDC

4 ATDC

4.5 ATDC

5 ATDC

5.5 ATDC

  • Fuel: ethanol

  • Tracer: 10% acetone

  • l3.85

  • Rc: 16:1

Fuel Tracer PLIF(resolved single-cycle)

W16mars_4


Conceptual model of hcci
Conceptual model of HCCI

Assuming homogeneous distributions of P, l, EGR% and RR:

Ignition occurs when I reaches a critical value


Conceptual model of hcci1
Conceptual model of HCCI

Effect of heterogeneous air/fuel ratio



Turbulence and geometry effects on HCCI

+2

+2.5

+3

+3.5

+4

+4.5

+5

+5.5

Suppression of hot and reactive zones

Single cycle fuel tracer LIF sequences


Hcci activities in lund3
HCCI activities in Lund

  • Basic engine studies

  • Laser diagnostics

  • Combustion modeling - Chemical kinetics

  • Closed loop combustion control



Closed loop combustion control clcc
Closed loop combustion control, CLCC

Inlet

Conditions

(pin,Tin)

User

Inputs

HEATERS

PC

Status

Calculation

NI PCI 6054

WaveBook

516

n-heptane

i-octane

PID

Controllers

PressureTraces

Injector

Actuator


Control parameters
Control Parameters

6

x 10

15

Max dp/dCA

Max Pressure

10

Cylinder Pressure [Pa]

5

0

-40

-20

0

20

40

60

80

Controlled

  • CA50

  • Net IMEP:s

    Constraints

  • Peak pressure

  • Peak dp/dCA

  • Net heat release

3000

Heat Release

2000

Heat Release, Q [J]

1000

0

CA50

-1000

-40

-20

0

20

40

60

80

Crank Angle [deg ATDC]



Combustion timing
Combustion Timing

Ignition Diagram

15

10

5

Combustion phasing [CA 50]

0

40

50

60

70

80

90

100

-5

-10

Octane Number

S = d(CA50%) / d(Octane Number)



Unstable operation
Unstable Operation

35

Stable

Unstable

30

25

20

CA50 [°ATDC]

15

10

5

0

0

100

200

300

400

Cycle Index

@ 3 bar IMEP

@ 4.5 bar IMEP

Closed loop control switched off


Operating range
Operating range

280 kW (380 hk)

  • HCCI Diesel

  • 21 bar

  • 280 310 kW


Typical high load cycle
Typical high load cycle

200

2

180

1.8

160

1.6

140

1.4

120

1.2

Cylinder Pressure [bar]

Rate of Heat Release [kJ/CAD]

100

1

80

0.8

60

0.6

40

0.4

20

0.2

0

0

-30

-30

-20

-20

-10

-10

0

0

10

10

20

20

30

30

Crank angle [CAD]

Load limited by Peak Cylinder Pressure at 200 bar and maximum rate of pressure at 30 bar/CAD

IMEP net 17.4 bar

IMEP gross 20.4 bar

Animation Power



And now to something completely different
And now to something completely different:



Akroyd hot bulb engine 1890
Akroyd Hot Bulb Engine 1890

  • Low pressure early direct injection

  • Fuel mix with residual gas and air before combustion

  • Combustion started as temperature increase due to compression

Photo of model at the Science Museum, London UK


2 stroke hot bulb engine
2-Stroke Hot Bulb Engine

Photo of drawing displayed at the Smithsonian Museum ,Washington, US


Efficiency

Efficiency

40

30

20

DI

PC

10

SC

SI

0

HT

0

2

4

6

8

10

12

HB

[%]

b

h

BMEP [bar]

2002-01-0115





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